Cardiff Council's 'Usual Suspects' campaign carries the message: "There's no excuse for dropping litter."
The anti-grime crackdown will focus on three main points:
- Dog fouling
- Fly tipping
The council's waste team is also telling dog owners there is a fine of £75 if caught not cleaning up after their dogs.
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It should turn cloudier through the early hours with some patchy drizzle and some hill fog too.
It will be a breezy day with variable amounts of cloud and some bright or sunny spells.
RAF veteran Andy Davies says the Royal British Legion helped him get back on his feet after problems with alcohol.